I was telling you I prefer to keep the sour cherries in the freezer, it's easier and faster for me. But this involves a large freezer, dedicated exclusively to frozen vegetables and fruits. If you don't have a freezer for this job, I suggest my mother's recipe. I've used it to preserve the cherries in the jar for as long as I can remember and without any problem.
My mother didn't add sugar at all, I prefer to add a little so that the cherries aren't so sour afterwards.
What would we use them for in the winter - of course, pies and cakes, cherry dumplings, jellies, creams, so almost anything you want!
First of all, if you are buying them, I suggest you choose bigger ones, so that after boiling they are more than just the peel.
If that's how you get them from the tree, that's it, you make them the way they are.
So, wash well and drain the sour cherries - if you notice any worms, leave in salted water for about an hour and you have solved the problem. Only make sure to rinse them thoroughly afterwards :)
I remove the pits with the safety pin, so the cherries are not traumatized and the pulp is not destroyed.
I also tried various devices, tricks, but eventually I came back to my grandmother's method.
Just remove the pit gently with the smaller tip of the pin and you're done.
Place the pitted cherries in a bowl, sprinkle a little sugar on top and shake or mix very carefully.
Leave like this for 2-3 hours or even overnight (in the fridge or in a cold place) to release as much juice as possible.
This is how much juice my sour cherries released. It may be even more, depending on the variety of cherries.
Transfer to a large saucepan or pan and place over heat.
When they come to the boil, stir carefully and cook over medium heat for 5-10 minutes.
I suggest keeping the cooking time like this - otherwise, you risk making porridge.
Pour the hot cherries into dry and sterilized jars (preferably in the oven - 30 minutes at 120 C).
Seal with lids and allow to cool well before storing in the closet.
That's about it. They keep very well and this is a method tested for years in our family and not only ...
Enjoy!